Destructive Tuning Rings
Above are two models that show how destructive tuning rings can occur
Destructive Adjacent Tuning (above left)
- This occurs where a hard seismic event within the hydrocarbon tank converges with a hydrocarbon contact
- At approximately 1/4 wavelength separation from the intra-tank hard to the contact is maximum dampening of hard amplitude and this can produce a destructive adjacent tuning ring
- These are not commonly observed because the situation requires relatively significant elevation between the top reservoir tank and the contact and enough intra-tank reflectivity to produce an intra-tank hard event
- In the case of Tamar (pictured above left) the base B Sand is one of these intra-tank hard events that produces a destructive adjacent tuning ring in conjunction with the contact
Destructive Intersection Tuning (above right)
- This occurs at the actual intersection of a top hydrocarbon tank soft event and the contact itself
- To observe a destructive intersection tuning ring the wet downdip extension of the soft top hydrocarbon tank event must also be relatively soft. Commonly however this downdip extension is either close to zero impedance or hard so no destructive intersection tuning ring would be observed
- In the case of Tamar (pictured above right) the top B Sand is relatively soft downdip of the contact so a destructive intersection tuning ring is observed